After completing his PhD in Sweden, Björn Afzelius took a position at Johns Hopkins University (Baltimore, MD) with the idea of working on luminescent organisms. But his experiments weren't working, and “at the end of the year I was desperate,” he says. “I picked up some embeddings I had brought over from Sweden.”
Afzelius had tried to improve on existing electron microscopy (EM) contrast by preparing his samples using 40% osmium tetroxide—“a nasty mixture,” he says, “that I wouldn't touch now.” But the chemical did its trick. Earlier EM had revealed the now familiar 9 + 2 pattern of the axoneme (the functional core of both eukaryotic flagella and cilia), with 9 doublet microtubules surrounding a central pair. With the extra contrast, Afzelius could spot arms that reached from one outer doublet toward another. The presence of the arms turned out to correlate with the...
